Thank you Mark. No, George does not have a Pro-Link, but he took the ECM to Williams Detroit Diesel In Phoenix and got a printout of his engine calibration and it shows VSS enabled, cruise enabled, cruise auto resume disabled, cruise VSG disabled and cruise engine brake enabled. Also it shows VSS Type to be tail and VSS Signal as "switched". His ECM had the 30 pin connector witch supplies all the end users DDEC feature's like Cruise and Jake removed for some time and it showed corrosion. George cleaned and inspected all the pins of the ECM but so far with no success. Ben

Ben, The dealer should have been able to give you a print out of how the selectable pins were configured. It would give you pin locations instead of wire numbers but that's all you need. The attached picture is from a DDEC V It very similar to DDEC III & IV just the pin descriptions are different. DDEC II does not have fan control.

Ken, thank you for your reply. We got a print out from Detroit Diesel but I am having a hard time understanding what I am reading. Prevost shows they are using wire 555 and 563 from the engine harness. That is the way we installed it. I have the print out from Detroit and wonder if you could take a look at it and be able to see if all the wires we need are really active. If you don't mind doing this I will email you the print out using the email address of your profile.Ben

Mark, I was wrong when I suggested that the VIN # is not in the Pro-Link DDEC III, I was wrong. I just installed my Pro-Link and found it on my S-60. The reason I never noticed , when Detroit Diesel programed my engine they entered my name and not the VIN #. I just contacted George, he has a Pro-Link from a friend and should be able to retrieve it if it ever was installed.Ben

Here's the pin connector locations from your print out from the Detroit Dealer. The connectors are viewed from the front (pin side). First thing is make sure you are using the correct wires and there is continuity form the pin to the end of the wire . A2 location on the Vehicle is fan control and W3 on the engine side is fan control. It seems strange that one fan control is on the vehicle harness and on is on the engine harness. F1 is for the fan over ride switch, when you ground this input it activates the fan #1 control no matter water temp. Let's go from there on your Fan problem. I put up some pictures of the programmable I/O's. As you can see there are several that the vehicle manufacturer can chose the function. Study the pictures and let me know what you think.

On the Cruise / Jake problem I noticed pin J2 is programed for a clutch switch. You don't have a clutch, right?

Ken , thank you for your input. I just got the word from my friend and he grounded J2 and both the jakes and cruse are now working. I have no idea for what reason someone activated the clutch function. This is an original engine and transmission of a 1995 Prevost XL model bus. But any way, the problem is fixed and we are now have a happy bus owner. Thank you again for your time and knowledge. Ben

Ken, I have been away from home for a few days. To answer your question, the answer is no. I think I know what the problem is, we probably need to ground the F1 wire of the ECM, but have not done it yet. At the moment, I am trying to convince George that the Lining Fan Clutch is the wrong clutch for his application on an Eagle Bus with a 12 Volt power supply. We had to install a voltage converter from 12 to 24 Volts. My worry is, this converter is a small electronic device and needs to be installed in a cool place. In the back of that Eagle bus there is no cool area. Because of this, there is a great potential for this converter to fail. If it does, the fan will completely stop and the engine will overheat within minutes. This can happen any time, even in the middle of winter when you hardly pay any attention to your engine temperature gage. I like to see him install a Horton two speed pneumatic fan clutch instead. If those clutches fail, they stay in high speed mode till the problem is fixedBen

If your printout is like Georgeís when F1 (Fan over ride) is grounded A2 or W3 will be grounded. I canít remember if FAN CNTRL 1 or 2 is high, I think itís 2. Itíll be easy to tell, ever which one is grounded when F1 is grounded. On Georgeís print out I think E1 is for an air conditioner input, it's for turning on the fan when the A/C is switched on. Tricky thing is that it needs to be disconnected / ungrounded when the A/C is on, so it usually needs to be controlled through a relay. If E1 is what I think it is the fan will always be locked up unless E1 is grounded. The logic is that if there is a circuit failure the fan would be on which of course is better than the alternative. If you use a ProLink or DDL to monitor the fan control status it will show ďFan Control OffĒ when the fan is engaged and ďFan Control OnĒ when disengaged. In other words "fan control on" is keeping the fan off. Clear as Mud?

This is why I decided to use a 2 speed Horton (not saying it's right). I occasionally stop by Hemphillís here in Nashville to see a friend and I always check the scrap pile out back. There is usually about a dozen Prevost fan clutches in the pile and Iím reasonably sure they are the Lining brand. I could not find anywhere to buy any bearings or other parts for those clutches. Now, to be fair Hemphillís has maybe 80 or 100 entertainer coaches on the road. So thatís probably a low failure rate. Bearings and clutches are readily available for the two speed Horton clutch I used. The Hortonís low speed is driven by opposing magnets and is not a direct drive and runs at about half speed (according to Hortonís Tech line). My thinking is that the charge air cooler most always needs air flow even in the winter, the exception maybe on deceleration or idle. I also think the engine compartment always needs some air flow, it gets really hot even with the fan on. This fan is locked on high without air pressure, applying air pressure unlocks the friction disc and allows the magnets to drive the fan. Another advantage of this system is that a vehicle with the radiator on the side is constantly cycling the fan. If the fan is already running at half speed itís much easier on the fan clutch and drive mechanism when it engages, instead of having to accelerate the fan from a dead stop to engine RPM.

Hereís what I think are 2 downsides the Horton clutch.

The fan I used has no bolts or other means of locking up the clutch if the friction disc fails.

There is no off on the clutch I used. It would be nice to be able to disengage the fan at times, but the option is not there on this fan

Ben/ George, Sam Caylor in Kansas was a big help to me on the Horton clutch. I stopped and picked up a clutch, angle box, and driveshaft from an MCI.( I think it was an E model). I got all the parts because they are tested on the MCI and I am not sure the Eagle angle box will stand up to all that shifting of the fan clutch. The angle box is made by Hub City ( a 600 series ) but MCI had hub city but tapered shafts on the box. When MCI did that it took the price of the box from around 600 (for straight shaft) to 3000+ for the Same box with tapered shafts (now an MCI part )